PA107DP

PA107DPU

5

P r o d u c t I n n o v a t i o n F r o m

®

PIN DESCRIPTIONS

Pin #

Pin name

Description

1

IN

Summing Junction Input for Inverting Operational Amplifier

2

+V

AUX

+10V to +18V Supply for Input Circuits

3

-V

AUX

-10V to -18V Supply for Input Circuits

4

GND

Ground

5

Open Pin

6

Open Pin

7

Open Pin

8

+V

S

+20V to +100V Supply for Gain and Gate Driver Circuits

9

-V

S

-20V to -100V Supply for Gain and Gate Driver Circuits

10

-V

SP

-20V to -100V Supply for Output Source Follower

11

OUT

High Power Output of Amplifier

12

+V

SP

+20V to +100V Supply for Output Source Follower

3. GENERAL

Please read Application Note 1 “General Operating Considerations” which covers stability, power supplies, heat

sinking, mounting, current limit, SOA interpretation, and specification interpretation. Visit www.cirrus.com for design

tools that help automate tasks such as calculations for stability, internal power dissipation, current limit, heat sink

selection, complete Application Notes library, Technical Seminar Workbook and Evaluation Kits.

CAUTION

In order to achieve the highest speed with limited space short circuit protection and thermal protection were sacri-

ficed. Do not short the output. Note that if current limiting at 1.5 A could be used, and the output was shorted, internal

dissipation would be 150 W. This would still destroy the amplifier, albeit more slowly.

4. INTERNAL POWER DISSIPATION AND HEATSINK SELECTION

With the unique combination of high voltage and speed of the PA107, traditional formulas for heatsink selection will

falsely lower the apparent power handling capability of this amplifier. To more accurately predict operating tempera-

tures use Power Design1 revision 10 or higher, or use the following procedure:

Find internal dissipation (PD) resulting from driving the load. Use Power Design or refer to Apex Applications Note

1, General Operating Considerations, paragraph 7. Find total quiescent power (PD

(total supply voltage), plus 0.021 times the total V

by multiplying 0.001 by V

Calculate a heatsink rating which will maintain the case at 85°C or lower.

Where:

T

T

Calculate a heatsink rating which will maintain output transistor junctions at 150°C or lower.

Where:

T

R

Use the larger heatsink of these two calculations.

Power Design is an Excel spreadsheet available free from www.cirrus.com

R

-0.1°C/W

T

PD + PD

Q

R

-0.1°C/W

T

PD + PD

Q